PHP function to convert any string to base64 url friendly

base64url.php

<?php

function base64url_encode($data)
{
    $base64 = base64_encode($data);

    if ($base64 === false) return false;

    $url = strtr($base64, '+/', '-_');

    return rtrim($url, '=');
}

function base64url_decode($data, $strict = false)
{
    $base64 = strtr($data, '-_', '+/');

    return base64_decode($base64, $strict);
}